Respuesta :

2r ≤ 3(2r - 7)
2r ≤ 6r - 21
21 ≤ 6r - 2r
21 ≤ 4r
21/4 ≤ r
r
[tex] \geq [/tex] 21/4
r [tex] \geq [/tex] 5.25